Facultad Regional Córdoba

Permanent URI for this communityhttp://48.217.138.120/handle/20.500.12272/94

Browse

Author: search.filters.author.Anunziata , Oscar AlfredoSubject: search.filters.subject.SBA-3

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Optimization of the synthesis of SBA-3 mesoporous materials by experimental desing.
    (Univesidsad Tecnológica Nacional., 2015) Ponte , María Virginia; Rivoira , Lorena Paola; Cussa , jorgelina; Martínez , María Laura; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Anunziata; Cussa , jorgelina; Rivoira , Lorena Paola
    SBA-3 mesoporous materials are characterized by hexagonal regular arrangements of channels with diameters >2 nm, high specific surface areas and high specific pore volumes. In the work reported herein, experimental design-response surface methodology (RSM) is used to model and optimize the synthesis conditions for SBA-3 mesoporous materials. In this study, we evaluate the influences of surfactant/silica source molar ratios, aging times, temperature and pH on the synthesis of SBA-3 mesoporous materials by analyzing the XRD intensities pertaining to the [100] signal. Response surfaces were obtained using the BoxeBehnken design, and the combination of reaction parameters was optimized. By applying statistical methodology, higher levels of the objective function (XRD intensities pertaining to the [100] signal) were obtained using cetyltrimethylammonium bromide (CTAB)/tetraethyl orthosilicate (TEOS) molar ratios of 0.07 and 0.16, HCl/TEOS molar ratios of 8 and 11, reaction temperatures of 35 and 45 ◦C and aging times of 12e24 h. The mesoporous SBA-3 samples obtained were characterized using small-angle X-ray powder diffraction (XRD), BET, FTIR and 29Si NMR-MAS, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
  • Thumbnail Image
    Item
    Synthesis and characterization of 2D-hexagonal, 3D-hexagonal and cubic mesoporous materials using CTAB and silica gel.
    (Univesidsad Tecnológica Nacional., 2016) Martínez , María Laura; Falcón, Horacio; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo
    Highly ordered mesoporous materials SBA family (Santa Barbara Amorphous), with symmetry of two-dimen sional (2D)-hexagonal SBA-3, three-dimensional (3D)-hexagonal P63/mmc (SBA-7) and cubic Pm3n (SBA-1) were synthesized by a simple and easy procedure, designed using silica gel as a silicon source, CTAB (cetyltrimethylammonium bromide) as a structure-directing agent, in highly acidic conditions. The effect of the variation of temperature and reaction time allowed us to obtain the optimum condition to prepare SBA-1, SBA-3 and SBA-7 materials. The sodium silicate generated “in situ” by dissolution of the silica gel, at different con centrations of NaOH and the variation of the synthesis temperature and reaction time are the three factors which allow obtaining different SBA phases. Thus, the best SBA-3, SBA-1 and SBA-7 materials with well-ordered meso- porous system can be obtained in the range of 0.8, 0.9 and 1.0 NaOH concentration and 30 and 25 °C and 45, 2880, 1440 min (for SBA-3, SBA-1 and SBA-7 respectively)
  • Thumbnail Image
    Item
    Sílica Gel como fuente de silicio: Síntesis y caracterización de matrial mesoporoso.
    (Univesidsad Tecnológica Nacional., 2015) Ponte , María Virginia; Martínez , María Laura; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Martínez , María Laura
    El material mesoporoso SBA-3 fue sintetizado mediante el método sol-gel, utilizando silicato de sodio como fuente de silicio y bromuro de hexadeciltrimetilamonio (CTAB) como agente director de estructura en condiciones acidas. El silicato sódico se generó in-situ por disolución de silica gel en NaOH. Se estudió el efecto de la variación de temperatura, la concentración de NaOH, y el tiempo de reacción. El mejor material mesoporoso con estructura SBA-3 fue obtenido con las siguientes condiciones de síntesis: temperatura: 25ºC; tiempo de reacción: 45min; concentración de NaOH: 0.8M.
  • Thumbnail Image
    Item
    Synthesis of SBA-1, SBA-3 and SBA-7 mesoporous materials. Study of the effect of time and temperature.
    (Univesidsad Tecnológica Nacional., 2018) Martínez , María Laura; Ponte , María Virginia; Falcón, Horacio; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Ponte , María Virginia
    In recent years, physicists, chemists and engineers have focused their research on the design of new functional materials. In the synthesis and control of materials in nanometer dimensions, the aim is currently directed towards the development of systems and devices that take advantage of chemical properties and physical principles, where their causes lie in the nanometer scale. Although there are numerous investigations about the synthesis of mesoporous materials from inorganic silicon salt, for example the synthesis of SBA-3. Ting et al [1] studied the synthesis of SBA-1; they obtained mesoporous SBA-1 with cubic structures, with a high porous system, by utilizing agents’ routers short chain structure such as the dodecyltrimethyl ammonium chloride. Recent research also showed that the formation of mesophases is affected by the presence of the counter ions and templates or surfactants can adopt a mesophase or other phases. So, Che et al. [2] found a phase shift 2D-hexagonal cubes from P6mm to Pm3n. We have published results for synthesis of SBA-3 with silica gel as silica source; we have found that the formation of mesophase is function of NaOH concentration in the dissolutions of silica gel. The influence of reaction temperature, time and NaOH concentration was investigated. During studies for the best synthesis conditions for synthesis of SBA-3, we also obtained SBA-1 and SBA-7 mesoporous materials.
  • Thumbnail Image
    Item
    Optimización de la síntesis del material mesoestructurado SBA-3 mediante diseño experimental.
    (Univesidsad Tecnológica Nacional., 2016) Ponte, María Virginia; Rivoira , Lorena Paola; Cussa , Jorgelina; Martínez , María Laura; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Martínez , María Laura; Cussa , jorgelina; Rivoira , Lorena Paola
    El material SBA-3 está constituido por una estructura de sílice mesoporosa de ordenamiento de poros regular hexagonal, diámetro de poro >3nm; presenta alta área superficial y alto volumen de poro. Se utilizó la metodología de Superficie de Respuesta para el modelado y optimización de las condiciones de síntesis de SBA-3. Se analizaron como factores del Diseño la influencia de la relación molar entre el surfactante (CTAB) y la fuente de silicio (TEOS), el tiempo de envejecimiento, la temperatura y el pH de la síntesis utilizando HCl. La respuesta analizada fue la intensidad de difracción de rayos X para el plano [100]. Las superficies de respuestas se obtuvieron con el diseño Box–Behnken, buscando la combinación de los parámetros que dieran como resultado la mejor estructura en el material sintetizado. Mediante la aplicación de metodología estadística, los mayores valores de la función objetivo (intensidad de DRX para el plano [100]) se obtuvieron utilizando valores de la relación molar CTAB/TEOS de 0,07-0,16; HCl/TEOS de 8-11; temperatura de síntesis de 35-45 (ºC) y tiempos de envejecimiento de 12-24hr.